Method of making multiplanar devices of sheet plastic

ABSTRACT

A multiplanar device has at least one component that consists of two rigid plastic wall members that have major areas of substantially uniform thickness, strips of considerably greater thickness along the side portions of said wall members, and a miter joint between the two wall members. A continuous thin film of flexible plastic is bonded to the two wall members and around the outside of the miter joint. 
     The method of making the component is to mold it as a flat intermediate piece with a V-notch between the strips of greater thickness and to simultaneously bond the film to the surface at the apex of the V; and to thereafter apply adhesive to the sides of the V and bend the piece to bring the sides of the notch together and bond them together. 
     Several such components may be connected with the similar or dissimilar components at miter joints to form a complete multiplanar device.

This is a division, of application Ser. No. 180,097 filed Aug. 21, 1980,now U.S. Pat. No. 4,352,843.

BACKGROUND OF THE INVENTION

A vast amount of work has been done upon making decorative, multiplanararticles by plastic molding; and in addition a good deal of work hasbeen done upon techniques for producing plastic moldings in the form ofsimulated, leaded stained glass. Patents in these fields which are knownto applicant include the following:

U.S. Pat. No. 4,110,393, for making plastic simulations of such articlesas Tiffany-type lamp shades.

U.S. Pat. No. 4,016,235, for making simulated stained glass.

U.S. Pat. No. 4,009,309 for making three-dimensional plastic articleshaving a stained glass effect.

U.S. Pat. No. 3,518,146 for making ornamental objects with simulatedinlaid designs.

U.S. Pat. No. 3,382,134, for producing simulated, leaded Venetian glass.

U.S. Pat. No. 3,122,598 for producing plastic articles such asdinnerware provided with a decorative surface insert.

SUMMARY OF THE INVENTION

The present invention relates to the manufacture of decorative,multiplanar articles from plastic. Such articles may be, for example,multiplanar lamp shades, or hexagonal or octagonal containers, ormultiplanar closed shapes such as a pyramid, a frustum of a pyramid, acube, or a solid having more than six surfaces.

In accordance with the present invention a multiplanar device has atleast one component that comprises first and second polygonal wallmembers of substantially rigid molded plastic which have major areas ofsubstantially uniform thickness, with the wall members having stripsalong their adjacent side portions which are substantially thicker thanthe major areas, and with the adjacent sides of the wall members forminga miter joint which positions the wall members at a predetermined angleto one another. The panels are bonded together at the miter joint, and athin film of flexible plastic is bonded to substantially the entirety ofthe wall members and forms a connection between the wall members aroundthe outside of the miter joint.

In order that a component as above described may be joined with othersimilar or dissimilar components to form a complete, multiplanar device,each of the first and second wall members has a strip along each sideportion which is substantially thicker than the major areas of the wallmembers, and each side of each wall member is a miter constructed andarranged to permit a plurality of components, all having thickenedstrips along each side and with the sides being miters, to be bonded toone another along the miters to form the multiplanar device.

In a component for a device such as a cube, each thicker strip isdefined by an inwardly projecting rib; while for something like asimulated leaded glass article, each thicker strip is defined by anoutwardly projecting rib which simulates the appearance of the leadingbetween panes of glass.

The method of making a component as above described is to mold the rigidwalls in a single plane with a V-notch between the strips of greaterthickness and with the thin film bonded to the walls across the apex ofthe V-notch in a single step. Thereafter adhesive is applied to thesides of the V-notch and the intermediate piece is bent along theV-notch to bring the surfaces of the notch into contact and adhere themto one another, so as to form the component having two walls connectedby a miter joint.

The surface of the film is provided with any desired decorative materialbefore it is bonded to the walls.

In the case of an article which has the thicker strips defined byoutwardly projecting ribs, the thin film of flexible plastic material isvacuum formed to provide it with a recess which defines the narrowstrips of greater thickness, and the vacuum formed film is placed in amold one face of which has a groove such that the mold face completelysupports the thin film including the recess. The simultaneous moldingand bonding is carried out in said mold with the flexible film in themold.

In the latter type of operation, the decorative material must be appliedto the surface of the film before it is vacuum formed, and the shape ofthe material as applied is so distorted from the desired final shapethat it assumes said final shape during vacuum forming.

The present method greatly simplifies and cheapens the manufacture ofmultiplanar devices by permitting the components to be produced entirelyin planar molds, after which the adjacent walls are bent, or folded to adesired angular relationship in a simple fixture which holds them untilthe connecting adhesive is set.

The rigid wall material may conveniently be polystyrene; while the thinfilm must be sufficiently flexible to be capable of vacuum preformingand bending at the miter joint. A vinyl or polyester film about 0.0015or 0.002 inch thick is satisfactory.

THE DRAWINGS

FIG. 1 is a perspective view of a multiplanar lamp shade of a type thatmay be made from components of the present invention;

FIG. 2 is a fragmentary sectional view on an enlarged scale takensubstantially as indicated along the line 2--2 of FIG. 1;

FIG. 3 is one type of intermediate piece that may be used to make theentire multiplanar device of FIG. 1;

FIG. 4 is a fragmentary sectional view on an enlarged scale takensubstantially as indicated along the line 4--4 of FIG. 3;

FIG. 5 is a view like FIG. 4 after the miter joint has been formed;

FIG. 6 is a fragmentary sectional view on an enlarged scale takensubstantially as indicated along the line 6--6 of FIG. 1;

FIG. 7 is a fragmentary sectional view on an enlarged scale takensubstantially as indicated along the line 7--7 of FIG. 3;

FIG. 8 is a plan view on an enlarged scale of an alternative type ofintermediate piece that may be used for the end of a device such as thatof FIG. 1;

FIG. 9 is a perspective view of a component produced from theintermediate piece of FIG. 8;

FIG. 10 is a fragmentary perspective view of a hexagonal device whichmay be used as a container, or a decorative pillar or the like;

FIG. 11 is a fragmentary sectional view on an enlarged scaleillustrating the adjacent parts of two walls of an intermediate pieceused in fabricating the structure of FIG. 10;

FIG. 12 is a fragmentary sectional view on an enlarged scale takensubstantially as indicated along the line 12--12 of FIG. 10;

FIG. 13 is a perspective view of a cube which may be fabricated inaccordance with the present invention;

FIG. 14 is a fragmentary sectional view on an enlarged scaleillustrating adjacent wall portions of an intermediate piece that may beused in fabricating the cube of FIG. 13; and

FIG. 15 is a fragmentary sectional view on an enlarged scale takensubstantially as indicated along the line 15--15 of FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings in detail, and referring first to FIGS. 1 to5, a multiplanar device such as a lamp shade consists of a polygonal topwall 20; two sides, such as the side indicated generally at 21, each ofwhich consists of an upper inclined wall 22 and a lower upright wall 23;and two end assemblies, indicated generally at 24. Each of the endassemblies has inclined walls 25, 26 and 27, and vertically dependingwalls 28, 29 and 30.

All the walls are connected with one another by miter joints theconstruction of which is best seen in FIGS. 2 and 5. Each of the upperinclined walls 22 is connected to the top wall 20 by a miter joint 31,and to the lower upright wall 23 by a miter joint 32. The inclined walls25, 26 and 27 of each of the end assemblies 24 are connected to the topwall 20 by respective miter joints 33, 34 and 35. Additional miterjoints 36 connect the inclined walls 25 to the vertically dependingwalls 28, miter joints 37 connect the inclined walls 26 to thevertically depending walls 20, and additional miter joints, notillustrated in their finished form, connect the inclined walls 27 to thevertically depending walls 30. All the miter joints 31 through 37 arepartially preformed, as illustrated in FIGS. 3 and 4.

In addition to the partially preformed miter joints 31 to 37, thefinished assembly also includes miter joints such as the joint 38illustrated in FIG. 6 which connects the lower upright side wall 23 withthe vertically depending wall 29 which is a part of the end assembly 24.Miter joints such as the joint 38 are not partially preformed in thesame sense as are the joints 31 through 37, because the walls connectedby joints such as the joint 38 were originally separate as seen in FIG.3, and are only joined in the final forming of the multiplanar device.Joints like the joint 38 include a joint 39 between the upper inclinedside wall 22 and the inclined wall 26 of the end assembly, and furthermiter joints which connect all the adjacent inclined walls and all theadjacent upright and vertical walls to one another to complete a closedfigure.

Referring now particularly to FIG. 3, an intermediate piece 100 ismolded flat and includes polygonal wall members of substantially rigidmolded plastic which have major areas of substantially uniform thicknessthat provide the several walls 20-30. A suitable material for the wallmembers is polystyrene. Bonded to an entire surface of the intermediatepiece 100 is a thin plastic film 101 which must be sufficiently flexibleto be capable of vacuum preforming and bending at the miter joints. Avinyl or polyester film about 0.0015 to 0.002" thick is satisfactory.

The intermediate piece 100 is formed in a mold cavity which is shaped toprovide partially preformed miter joints, as indicated generally at 131in FIG. 4; and preformed miters, as indicated at 128 in FIG. 7. Each ofthe partially preformed miter joints such as 131 includes a strip 120along a side portion of the top wall 20 which is substantially thickerthan the major area of said top wall, and an identical strip 122 alongthe adjacent side portion of the upper inclined wall 22. The thickenedstrips 120 and 122 have adjacent faces 120a and 122a which define a 45°V-notch 123. The thin, flexible plastic film 101 extends completelyaround the thickened strips 120 and 122 and serves as a hinge across theV-notch 123. It is to be understood that there are partially preformedmiter joints like the preform 131 along all the junctions between thetop wall 20 and the inclined walls 22, 25, 26 and 27, and along thejunctions between said inclined walls and the respective upright, orvertically depending walls 23, 28, 29 and 30.

Referring now to FIG. 7, the miter 128 is seen to consist of a thickenedstrip along a marginal portion of the wall 28, with said thickened striphaving an inclined surface 128a which may meet with a complementarilyinclined surface of a thickened miter strip 129 along the adjacentmarginal portion of the wall 29, so that said miters may form a miterjoint as seen in FIG. 6. It is understood, of course, that all the walls22-30 have thickened miter strips like the miter strips 128 and 129along their end marginal portions, so that all the adjacent miters maybe joined into miter joints like the miter joint 38.

In addition, as best seen in FIG. 2, each of the lower upright walls 23and each of the vertically depending walls 28, 29 and 30 has a thickenedlower marginal strip such as the strip 123 illustrated in FIG. 2. Suchstrips are purely decorative, and in a device such as that illustratedin FIG. 1 may be shaped and colored to provide the appearance of aleaded margin which cooperates with all the other thickened marginalstrips to present the appearance of lead framing around glass panels.The walls may, of course, be of any color or variety of colors so as tosimulate stained glass.

In a preferred method of fabricating an intermediate piece such as piece100, the thin film 101 is first vacuum formed to provide it withrecesses such as the recess indicated generally at 102 in FIG. 4, therecess indicated generally at 103 in FIG. 7, and the recess indicatedgenerally at 104 in FIG. 2. All such recesses fit into grooves in a faceof the mold cavity in which the intermediate piece 100 is formed, so themold cavity face completely supports the thin film 101 including therecesses. The material for the wall members 20-30 is introduced into themold cavity with the thin film 101 supported upon said face, so that thewall members of the intermediate piece are formed and simultaneouslybonded to the thin film 101.

The foregoing steps are described in more detail in U.S. Pat. No.4,110,393, particularly from column 5, line 43 to column 6, line 46.

The intermediate piece 100 is removed from the mold and placed in afixture in which all the walls 22-30 may be bent at the partiallypreformed miter joints such as the joint 131. A bonding adhesive isapplied to all the sides such as the sides 120a and 122a of the V-notch123, so that when bending along the V-notches is carried out, theadjacent faces are bonded to one another as illustrated in FIG. 5. Atthe same time, the complementary faces of the miters such as the miters128 and 129 are also coated with adhesive so that when the walls arebent along the partially preformed miter joints the adjacent faces ofthe miters such as 128 and 129 are bonded to one another to form miterjoints such as the miter joint illustrated in FIG. 6.

It is quite apparent that an intermediate piece 100 as illustrated inFIG. 3 is practical only for the fabrication of a rather small device ofthe type illustrated in FIG. 1. A mold capable of producing a largeintermediate piece such as the piece 100 would be prohibitivelyexpensive. Accordingly, if a device the shape of that illustrated inFIG. 1 is to be made in a size large enough to be used, for example, asa billiard table lamp, separate intermediate pieces must be made for thesides like the sides 21A in FIG. 3, and for the ends such as the ends24A in FIG. 3. For that kind of large device, a sheet metal plate may besubstituted for the plastic top wall 20, and the intermediate side andend pieces may be bonded to the margins of the metal top plate.

FIG. 8 illustrates an intermediate piece 124A which is suitable forfabricating either end of a large lamp such as a billiard table lamp;and FIG. 9 illustrates a component produced from the intermediate piecefastened to the end of a metal top plate 20A. An intermediate piece 124Aas illustrated in FIG. 8 has partially preformed miter joints betweenthe wall members 25A and 28A, the wall members 26A and 29A, and the wallmembers 27A and 30A, and each such partially preformed miter joint isthe same as that illustrated in FIG. 4. In addition, there are partiallypreformed miter joints 140 between the wall members 25A and 26A, andbetween the wall members 25A and 27A. Additionally, there are miterslike the miter 128 illustrated in FIG. 7 along adjacent margins of thewall members 28A, 29A and 30A. Additionally, thickened miter strips 25B,26B and 27B are formed along the top margins of the wall members 25A,26A and 27A for bonding the fabricated piece part to the end margin ofthe metal top plate 20A as illustrated in FIG. 9.

Referring again to FIG. 4, it is apparent that the bottom of the V-notch123 must be at the flexible film 101, or so close to it that the moldedplastic below the V-notch can crack cleanly when it is bent.

Turning now to FIGS. 10 to 12, a multiplanar article takes the form of ahexagonal body, indicated generally at 220, which may be used for any ofa variety of purposes. Thus, for example, the body 220 may be providedwith a fixed bottom to make a container like a wastebasket. It may belong enough to provide a decorative column between top and bottomstructural members. It may be connected to a base and have a largeplanar top mounted upon it, so that it provides the pedestal for atable. It may be a horizontally extending decorative element extendingbetween two upright panels.

The body 220 has walls 221, 222, 223, 224, 225 and 226, and the entireouter surface of the article is enclosed in a thin, flexible film 201which is bonded to the bodies of the walls.

As seen in FIG. 11, an intermediate piece, indicated generally at 200,for the body 220 has one or more partially preformed miter joints,indicated generally at 231; and said partially preformed miter jointcomprises a thickened strip 241 extending along a marginal portion ofthe wall 221, a thickened strip 242 extending along a marginal portionof the wall 222, and faces 241a and 242a of said strip define a V-notch243 having an angle of 60° between its sides.

The number of partially preformed miter joints in an intermediate piece200 for a hexagonal body 220 depends upon the widths of the walls221-226. If the walls are narrow enough to economically form all six ofthem in a single mold, then there will be five partially preformed miterjoints and one miter joint, indicated generally at 238 in FIG. 10, whichjoins the wall 226 to the wall 221 by abutting a miter strip 248 on thewall 226 with a miter strip 249 on the wall 221 and bonding them withadhesive.

If the walls of the hexagonal body are too wide to make a single moldfor all six walls practical, then an intermediate piece may consist ofeither two walls or three walls, again depending upon the practicalitiesof mold making. Thus, there might be one intermediate piece for thewalls 221, 222 and 223, and a second intermediate piece for the walls224, 225 and 226. In that case, of course, there would be two partiallypreformed miter joints in each intermediate piece, and the twointermediate pieces would be joined along their adjacent walls by miterjoints like the joint 238 in FIG. 10.

If the walls are wide enough, it may be necessary to have threeintermediate pieces, each consisting only of two walls.

In any case, the intermediate piece or intermediate pieces are placed ina fixture and bent at the V-notches 243 to bring adhesive coated faces241a and 242a into abutment as seen in FIG. 12. At the same time, anymiter joint such as the joint 238, to join two independently formedintermediate pieces, is made as previously described with respect to thefirst embodment.

Referring now to FIGS. 13 to 15, a cube, indicated generally at 320, hassix identical walls such as the walls 321, 322 and 323. As seen in FIG.14, at least the two walls 321 and 322 are fabricated from a flatintermediate piece 300 having a continuous flexible film 301 coveringits lower surface, which becomes the outer surface of the cube.Thickened miter strips 341 and 342 along the adjacent martinal portionsof the respective wall members 321 and 322 have respective faces 341aand 342a which are at right angles to one another and define a notch 343to provide a partially preformed miter joint 331.

The two wall members 321 and 322 are brought to the position illustratedin FIG. 15, closing the notch 343 and adhering the surfaces 341a and342a to one another by means of adhesive.

There are, of course, several ways to fabricate a cube from intermediatepieces. There may be one intermediate piece to form the walls 321 and322, a second intermediate piece to form the wall 323 and the wallopposite the wall 322, and a third intermediate piece to form the wallopposite the wall 321 and to form the bottom wall. Alternatively, asingle intermediate piece may provide the walls 321, 322 and 323, and asecond intermediate piece may provide the other three walls. It is evenpossible to provide a single intermediate piece which forms all but onewall, and close the open side of the cube with a separate wall member.In any event, any marginal portion of a wall member which is not part ofa partially preformed miter joint has a thickened miter strip like thestrip 341 or 342, and having an inclined surface like the surface 341aor 342a, so that two such miter strips may be joined as previouslydescribed with reference to FIGS. 6 and 7 of the first embodiment of theinvention.

Whether the thickened miter strips are formed on the outer surfaces ofthe wall members as in the structure of FIGS. 1 to 9, or on the innersides of the wall members as in the structures of FIGS. 10 to 15,depends entirely upon the desired appearance of the finished article.

An advantageous feature of the present invention is that any decorativematerial may be printed upon the thin flexible film 101, 201 or 301 whenthe film is flat, making it possible to do such printing by conventionalmethods. If the thin outer film must be vacuum preformed, as is the film101, areas that are to be distorted to form recesses such as therecesses 102, 103 and 104 are printed with the distortion precalculatedso that the distorted areas present the desired final appearance, as iswell known in the art.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations should be understoodtherefrom as modifications will be obvious to those skilled in the art.

I claim:
 1. A method of making a component for a multiplanar devicehaving effectively planar, angularly related rigid molded plastic walls,said method comprising the successive steps of:molding a plasticintermediate piece which has two rigid walls having major areas ofuniform thickness in a single plane, narrow strips of substantiallygreater thickness along adjacent end portions of said walls, and aV-notch between said strips of greater thickness and, simultaneouslywith said molding, bonding a continuous thin film of flexible plasticmaterial to substantially the entirety of one surface of said walls toprovide a hinge at the apex of the V-notch; and thereafter applying anadhesive to the sides of said V-notch and bending said intermediatepiece along said V-notch to bring the surfaces of said notch intocontact and adhere them to one another, thereby forming a componentwhich has two walls connected by a miter joint.
 2. The method of claim 1which includes the step of decorating a surface of the film before saidfilm is bonded to the walls.
 3. The method of claim 1 in which the thinfilm of flexible plastic material is vacuum formed to provide it with arecess which defines the narrow strips of greater thickness, a mold isprovided with a face which has a groove such that said face completelysupports the thin film including the recess, and in which thesimultaneous molding and bonding is carried out in said mold with theflexible film in the mold.
 4. The method of claim 3 which includes thestep of applying decorative material to a surface of the film before itis vacuum formed, the shape of said material as applied being sodistorted from a desired final shape that it assumes said final shapeduring vacuum forming.